When a pill is swallowed, it undertakes a perilous journey before it can be absorbed by the body. Even if it manages to survive exposure to stomach acid and resist breakdown by digestive enzymes, the tablet must then penetrate the mucus barrier, the gut’s defense against unwanted particles.
Some large protein drugs, including insulin which treats diabetes and the antibiotic vancomycin, cannot cross the mucus barrier at all. Due to the strength of the barrier, less than 1 percent of insulin taken by mouth is absorbed and used by the body, forcing patients to inject themselves instead.
But in a new study published in Scientific robotics last week, researchers created a robotic pill that can break through the mucus barrier to deliver drugs more efficiently.
“I was watching videos of these machines that can make tunnels”, Shriya Srinivasanbiomedical engineer at MIT and lead author of the study, says new scientistis Alex Wilkins. “I thought, ‘OK, how about we do this but for mucus.’
The team’s robotic pill, called RoboCap, is about the size of a multivitamin. Inside, it holds the drug payload in a tiny compartment. The exterior is grooved, studded and coated with a gelatin that dissolves at a certain pH. When the pill is swallowed and reaches the stomach, the acidity erodes the coating. Then the pH of the small intestine triggers a motor inside the capsule that spins the pill.
The device’s textured surface removes mucus, and the spinning motion erodes the compartment with the drug payload, which is slowly released into the digestive tract. After about 35 minutes of activity, the capsule normally moves through the rest of the tract and exits the body with a bowel movement.
The researchers tested the pill’s ability to deliver insulin and vancomycin in excised pig small intestine tissue and in seven live pigs. Compared to a similar pill without a rotating mechanism, RoboCap increased the amount of drug absorbed by 20 to 40 times, according to the study.
In insulin tests on live pigs, the pill worked so well that an hour after giving birth, three of the animals became hypoglycemic from the drug. The researchers had to administer dextrose to raise the pigs’ blood sugar levels.
“This substantiates its significant potential to enable oral delivery of molecules that previously had little success by oral delivery,” the authors write in the paper. “Future studies in pigs and humans should optimize the dosing of these drugs to identify therapeutic ranges via SI [small intestinal] delivery.”
RoboCap could help patients avoid daily injections or prevent them from having to travel to the hospital to receive medication, which could be a “game changer”, Srinivasan said. Scientific News‘Meghan Rosen.
Further research should examine how the pill would affect people with weakened immune systems, as well as its impact on helpful bacteria living in the mucus of the gut, says Abdul Basita pharmacy researcher at University College London in England who was not involved in the study, to new scientist.
“RoboCap is an innovative concept that aims to overcome the current difficulty of orally administering many advanced and emerging therapies,” he adds.